The weapons in that animation are quite real, although I did use a computer program (GIMP) to edit out their transparent plastic stands. They were made completely from scratch (mostly from paper and white glue); here's some shots of them before they were painted:
And the finished product:
While I've made numerous guns from scratch over the years, I don't think I've ever made a flintlock pistol or arquebus. The basic shape of the gun wouldn't be too hard, but I imagine that the little hammer/striker/trigger elements might be tricky, as would engraving it if you wanted it to look fancy. I really can't think of much, other than Pirates of the Carribean, that would have that type of thing. I think that McFarlane Toys' Pirate Spawns had flintlock pistols, but they're 6-7" inch scale.
Another idea just occured to me: Considering that it's the Thanksgiving season, it's possible you might be able to find some pilgrim figurines with Blunderbusses. While that isn't exactly the type of weapon you're looking for, I imagine, if you cut off the bell-shaped end of the barrel of a Blunderbuss, the result would look something like a flintlock/matchlock weapon.